Microstructure and bonding strength of impact-welded aluminium stainless steel joints

An aluminium projectile was impact-welded on a stainless steel target using a nitrogen gas gun at an impact velocity over 250 m s(-1). Effects of surf ace roughness of the impact face of the target on the bonding area and the strength of the bending area were examined. The microstructure and element distribution in the joint were analyzed and the experimental results of con centrations of the elements in the compound layer at the interface were com pared with the theoretical values. The following results were obtained. It was clarified that the bonding strength of the area which increased with th e decrease of surface roughness was much lower than that of the region whic h was independent of surface roughness. The thickness of the compound layer formed at the interface increased with the impact velocity. The experiment al results of the concentrations of the elements in the layer hardly depend ed on impact velocity and were close to the theoretical results in which eq uivalent heat was generated at impact faces of the projectile and the targe t. (C) 1999 Elsevier Science S.A. All rights reserved.